1. Field of the Invention
This invention relates generally to a command interpreter for a vehicle stability enhancement system and, more particularly, to a command interpreter for a vehicle stability enhancement system that uses a three degree-of-freedom vehicle model with non-linear suspension and tire characteristics for calculating the stability command signals.
2. Discussion of the Related Art
Various vehicle stability control systems are known in the art that improve driver convenience, safety and comfort. These stability control systems typically employ differential braking, active or semi-active suspension, active front steering and/or active rear wheel steering to provide the stability control. The control system measures the driver's desire of vehicle performance to control inputs, such as steering wheel, brake pedal, etc., and compares the vehicle response with the desired maneuver. The vehicle stability control system usually includes a command interpreter to determine the driver's desire.
The stability control system typically receives vehicle dynamics information from various sensors, such as yaw rate sensors, lateral acceleration sensors, vehicle speed sensors, wheel speed sensors, hand-wheel angle sensors, tire force sensors, wheel force sensors, roll rate sensors, etc. to calculate or estimate various vehicle parameters and states. The vehicle parameters and states are then used to provide actuator command signals to provide the stability control. For vehicle rollover control, it is typically important to limit roll motion and side-slip motion in addition to yaw motion. Therefore, in order to provide rollover mitigation, suitable command signals are typically required for generating the desired yaw-rate command, roll angle command and side-slip command.